Hello, i just fitted bathroom and fitted a swirl shower valve, i have a combi so i by passed the cwsc for mains pressure in bathroom, all was going well till i tried the basin mixer and found hot water pressure over powerd by the cold. have fitted a prv on the feed but still no good, also even with the iso valve almost closed on the cold you turn it on and the boiler fires up and you get hot water, with it fully open you get cold from both and still the boiler fires up when just cold on, could this be a problem with the tap itself. any help most welcome Thanks